1. Field of the Invention
This invention relates to improvements in solar energy photovoltaic systems, and more particularly, but not by way of limitation, to an inherent spectrum splitting photovoltaic concentrator system.
2. Description of the Prior Art
In the past, it has been known to employ dichroic mirrors to break light into selected component colors or to combine selected component colored light into a predetermined color. In U.S. Pat. No. 2,642,487 issued to A. C. Schroeder light entered through a lens strikes intersecting dichroic mirrors which break the light down into its component colors of blue, green and red by passing one component and reflecting the other components. Light component utilization means are positioned in each component path. However, the present invention avoids the use of dichroic mirrors with their associated losses and instability.
In U.S. Pat. No. 3,554,634 issued to W. L. Duda et al, the concept of beam splitting was seen in an optical logical device which included means for selectively positioning a single light beam at a plurality of discrete positions, and means placed in the path of the positioned beam for uniquely encoding a plurality of different values of characteristic of the positioned beam in accordance with each discrete position of the beam to provide an optical output which may be conveniently read-out to determine the result. It is apparent though that the disclosed system was directed only to optical logic and not to concentrating solar energy to maximum utilization.
In U.S. Pat. No. 2,742,550 a low temperature dual photoconductive infrared radiation detector cell is disclosed in an effort to overcome the serious limitation of infrared detection cells for the detection of weak signals. This particular infrared detector provided a first coating of photoconductive material sensitive to a first infrared wavelength band on one side of a dielectric layer and on the other side of the dielectric layer another coating of photoconductive material is disposed that is sensitive to a second infrared wavelength. A reflection reducing coating transparent to infrared radiation is disposed on the radiation receiving side of the second coating and a mirror surface is provided on the base of the device to reflect upwardly to the photoconductive layers any radiation that may have passed through such photoconductive layers and thereby capture within the cell all received infrared radiation. Such device obviously was only limited to detecting low level infrared radiation and does not concentrate and split a solar light spectrum into various energy band components for maximum utilization.
U.S. Pat. No. 3,569,763 discloses another photoconductive device wherein first layers of a photoconductive material having one spectral response region and second layers of a different photoconductive material having a different spectral response region are laminated on one another in predetermined order to provide an image pickup tube having a high sensitivity to light for color television broadcast. This device does not physically concentrate and split a solar energy beam into different paths for maximum utilization.